Functionalized polymers and improved vulcanizates therefrom

ABSTRACT

A functionalized polymer defined by the formula π-R 1 -α, where π is a polymer chain, R 1  is a bond or a divalent organic group, and α is a sulfur-containing heterocycle.

This application gains benefit from U.S. Provisional Application Ser.No. 60/453,693 filed on Aug. 30, 2002.

FIELD OF THE INVENTION

This invention relates to functionalized polymers and rubbervulcanizates prepared therefrom.

BACKGROUND OF THE INVENTION

In the art of making tires, it is desirable to employ rubbervulcanizates that demonstrate reduced hysteresis loss, i.e., less lossof mechanical energy to heat. Hysteresis loss is often attributed topolymer free ends within the cross-linked rubber network, as well as thedisassociation of filler agglomerates. The degree of dispersion offiller within the vulcanizate is also important, as increased dispersionprovides better wear resistance.

Functionalized polymers have been employed to reduce hysteresis loss andincrease bound rubber. The functional group of the functionalizedpolymer is believed to reduce the number of polymer free ends. Also, theinteraction between the functional group and the filler particlesreduces filler agglomeration, which thereby reduces hysteretic lossesattributable to the disassociation of filler agglomerates (i.e., Payneeffect).

Conjugated diene monomers are often anionically polymerized by usingalkyllithium compounds as initiators. Selection of certain alkyllithiumcompounds can provide a polymer product having functionality at the headof the polymer chain. A functional group can also be attached to thetail end of an anionically-polymerized polymer by terminating a livingpolymer with a functionalized compound.

For example, trialkyltin chlorides, such as tributyl tin chloride, havebeen employed to terminate the polymerization of conjugated dienes, aswell as the copolymerization of conjugated dienes and vinyl aromaticmonomers, to produce polymers having a trialkyltin functionality at thetail end of the polymer. These polymers have proven to betechnologically useful in the manufacture of tire treads that arecharacterized by improved traction, low rolling resistance, and improvedwear.

Because functionalized polymers are advantageous, especially in thepreparation of tire compositions, there exists a need for additionalfunctionalized polymers. Moreover, because precipitated silica has beenincreasingly used as reinforcing particulate filler in tires,functionalized elastomers having affinity to silica filler are needed.

SUMMARY OF THE INVENTION

In general the present invention provides a functional polymer that isdefined by the formulaπ-R¹-αwhere π is a polymer chain, R¹ is a bond or a divalent organic group,and α is a sulfur-containing heterocycle.

The present invention also includes a method for preparing a functionalpolymer, the method comprising terminating a living polymer chain with afunctionalizing agent where the functionalizing agent is defined by theformulaZ—R⁴-αwhere Z is a leaving group or an addition group, R⁴ is a bond or adivalent organic group, and α is a sulfur-containing heterocycle.

The present invention further provides a vulcanizate prepared byvulcanizing a rubber formulation comprising at least one vulcanizablerubber and a filler, where the at least one vulcanizable rubber is afunctional polymer that is defined by the formulaπ-R¹-αwhere π is a polymer chain, R¹ is a bond or a divalent organic group,and α is a sulfur-containing heterocycle.

The functionalized polymers of this invention advantageously providecarbon black, carbon black/silica, and silica filled-rubber vulcanizateshaving reduced hysteresis loss, improved wear, and improved wettraction. Also, filled-rubber vulcanizates prepared with thefunctionalized polymers of this invention exhibit a reduced Payneeffect. Excellent polymer processability is maintained. Thesefunctionalized polymers can be readily prepared by terminating livingpolymers.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

This invention relates to functionalized polymers defined by the FormulaIπ-R¹-αwhere π is a polymer chain, R¹ is a bond or a divalent organic group,and α is a sulfur-containing heterocycle.

The polymer chain (π) substituent of the functionalized polymer ispreferably a rubbery polymer. More preferably, the polymer chainsubstituent is a polymer that has a glass transition temperature (Tg)that is less than 0° C., more preferably less than −20° C., and evenmore preferably less than −30° C.

Preferred polymers include anionically polymerized polymers. Morespecifically, preferred polymers include polybutadiene, polyisoprene,poly(styrene-co-butadiene), poly(styrene-co-butadiene-co-isoprene),poly(isoprene-co-styrene), and poly(butadiene-co-isoprene). The polymer(π) may include a functional group at the head of the polymer, whichresults from initiating polymerization with a functionalized initiator.

In general, the polymer should have a number average molecular weight(M_(n)) of from about 5 to about 1,000 kg/mole, preferably from about 50to about 500 kg/mole, and more preferably 100 to about 300 kg/mole, asmeasured by using Gel Permeation Chromatography (GPC) calibrated withpolystyrene standards and adjusted for the Mark-Houwink constants forthe polymer in question.

R¹ is a bond or a divalent organic group. The divalent organic group ispreferably a hydrocarbylene group or substituted hydrocarbylene groupsuch as, but not limited to, alkylene, cycloalkylene, substitutedalkylene, substituted cycloalkylene, alkenylene, cycloalkenylene,substituted alkenylene, substituted cycloalkenylene, arylene, andsubstituted arylene groups, with each group preferably containing from 1carbon atom, or the appropriate minimum number of carbon atoms to formthe group, up to about 20 carbon atoms. In a preferred embodiment, R¹contains a functional group that will react or interact with carbonblack or silica.

“Substituted hydrocarbylene group” is a hydrocarbylene group in whichone or more hydrogen atoms have been replaced by a substituent such asan alkyl group. R¹ may also contain one or more heteroatoms such as, butnot limited to, nitrogen, oxygen, silicon, sulfur, and phosphorus atoms.

The sulfur-containing heterocycle α comprises a closed-ring structure inwhich one or more of the atoms in the ring is sulfur. Suitablesulfur-containing heterocycles may comprise more than one ringstructure. In addition, suitable sulfur-containing heterocycles maycomprise other heteroatoms, such as nitrogen, oxygen, silicon, andphosphorus. Suitable sulfur-containing heterocycles may comprisesaturated rings, partially unsaturated rings, aromatic rings, or acombination thereof.

Examples of sulfur-containing heterocycle groups include thiirane,thietene, thiolane, thiazole, thiazoline, thiazolidine, thiadiazole,thiophene, dihydrothiophene, benzothiophene, naphthothiophene,thienothiophene, thiadiazine, dithiazine, thioxanthene, thianthrene,phenoxathiin, benzothiazole, isothiazole, dihydroisothiazole,thienofuran, thiomorpholine, thialdine, and substituted forms thereof.

Preferred sulfur-containing heterocycles comprise at least one ringhaving five or six members. Preferred five-member ring heterocyclesinclude thiazoline, thiophene, and thiazolyl groups.

In one preferred embodiment, the functional polymer includes athiazoline group, and the functionalized polymer can be defined by theformula

where π and R¹ are as defined above, each R² is independently hydrogenor a monovalent organic group, each R³ is independently hydrogen or amonovalent organic group, or where each R³ combine with each other toform a divalent organic group.

The monovalent organic groups are preferably hydrocarbyl groups orsubstituted hydrocarbyl groups such as, but not limited to alkyl,cycloalkyl, substituted cycloalkyl, alkenyl, cycloalkenyl, substitutedcycloalkenyl, aryl, allyl, substituted aryl, aralkyl, alkaryl, andalkynyl groups, with each group preferably containing from 1 carbonatom, or the appropriate minimum number of carbon atoms to form thegroup, up to 20 carbon atoms. These hydrocarbyl groups may containheteroatoms such as, but not limited to, nitrogen, oxygen, silicon,sulfur, and phosphorus atoms. The preferred monovalent organic groupswill not react with a living polymer.

In another preferred embodiment, the functional polymer includes athienyl group, and the functional polymer can be defined by the formula

where π, R¹ and R² are as defined above, or where two or three R² groupscombine to form a multivalent organic group. In this embodiment, R¹optionally contains one or more heteroatoms such as, but not limited to,nitrogen, oxygen, silicon, sulfur, and phosphorus atoms. Preferably, R¹contains nitrogen.

In yet another preferred embodiment, the functional polymer includes abenzothiazole group, and the functional polymer can be defined by theformula

where π, R¹ and R² are as defined above, or where two or three R² groupscombine to form a multivalent organic group. In this embodiment, R¹preferably contains one or more heteroatoms such as, but not limited to,nitrogen, oxygen, silicon, sulfur, and phosphorus atoms.

An example of a functionalized polymer where R¹ contains a functionalgroup that will react or interact with carbon black or silica is whereR¹ contains a dialkoxysilyl group, and the functionalized polymer can bedefined by the formula

where π and α are as defined above, each R⁵ is independently amonovalent organic group, and R⁶ is a bond or a divalent organic group.

The functionalized polymers of this invention are preferably prepared byreacting or terminating a living polymer with a functionalizing agentcontaining a sulfur-containing heterocycle. Preferred functionalizingagents can be defined by the formulaZ—R⁴-αwhere Z is a leaving group (L) or an addition group (A), R⁴ is a bond ora divalent organic group, and α is as described above. Thefunctionalizing agent may react with a living polymer via a substitutionreaction or an addition reaction.

In one embodiment, the functionalizing agent is a substitution-typefunctionalizing agent that can be defined by the formulaL-R⁴-αwhere L is a leaving group, and R⁴ and α are as described above. Thisfunctionalizing agent reacts with the living portion (i.e. —C⁻) of thepolymer chain via a substitution reaction in which L is displaced and abond is formed between R⁴ and π. Where R⁴ is a bond between L and α, Lis displaced and a bond is formed between α and π. Thus, in this case,R⁴ is equivalent to R¹ in Formula I above.

Leaving groups include those substituents that can be displaced by annucleophilic compound, such as a polymer anion. Preferably the leavinggroup (L) will react or associate with the living polymer's countercation (e.g., Li⁺) and form a stable or neutral compound. Exemplaryleaving groups include halides, thio alkoxides, alkoxides and dialkylamines.

In one embodiment, where α comprises a thiazoline group, thefunctionalizing agent is defined by the formula

where L, R², R³, and R⁴ are as described above.

Useful functionalizing agents that comprise a thiazoline group include2-methylthio-2-thiazoline, 2-ethylthio-2-thiazoline,2-propylthio-2-thiazoline, 2-butylthio-2-thiazoline,2-pentylthio-2-thiazoline, 2-hexylthio-2-thiazoline,2-heptylthio-2-thiazoline, 2-dodecylthio-2-thiazoline,2-phenylthio-2-thiazoline, 2-benzylthio-2-thiazoline,2-chloro-2-thiazoline, 2-bromo-2-thiazoline, 2-iodo-2-thiazoline,2-dimethylamino-2-thiazoline, 2-diethylamino-2-thiazoline,2-methoxy-2-thiazoline, 2-ethoxy-2-thiazoline,2-(N-methyl-N-3-trimethoxysilylpropyl)-thiazoline, and2-methylthio-1-aza-3-thia-bicyclo[3-4-0]-nonene.

Another preferred functionalizing agent comprises a trialkoxysilanegroup and a sulfur-containing heterocycle, and can be defined by theformula

where α is as defined above, each R⁵ is independently a monovalentorganic group, and R⁶ is a bond or a divalent organic group. In thisembodiment, leaving group L is an alkoxide group (OR⁵) and R⁴ comprisesa dialkoxysilyl group.

Preferably, R⁶ comprises a functional group that will react or interactwith carbon black and/or silica. One preferred functional group is aSchiff base, generally represented as RR′C═NR″.

In one embodiment, the functionalizing agent of the present inventionincludes a trialkoxysilane group, a Schiff base group, and a thiophenegroup, and can be defined by the formula

where R⁵ is as described above, each R⁷ is independently a bond or adivalent organic group, and R⁸ is hydrogen or a monovalent organicgroup.

In another embodiment, the functionalizing agent of the presentinvention comprises a trialkoxysilane group and a thiazoline group, andcan be represented by the formula

where R², R³, R⁵, and R⁶ are as described above.

Useful functionalizing agents that comprise a trialkoxysilane group anda sulfur-containing heterocycle include2-(N-methyl-N-3-trimethyoxysilylpropyl)thiazoline,2-(N-methyl-N-3-trimethyoxysilylpropyl)thiophene,2-(N-methyl-N-3-trimethyoxysilylpropyl)thiazole, and the reactionproduct of 2-thienyl carboxaldehyde and aminopropyl trialkoxysilane.

In another embodiment, the functionalizing agent is an addition-typefunctionalizing agent that can be defined by the formulaA-R⁴-αwhere α and R⁴ are as described above, and A is an addition group or, inother words, a reactive moiety that will undergo an addition reactionwith the living portion (i.e. —C⁻) of the polymer chain (π). Thisfunctionalizing agent reacts with a polymer chain via an additionreaction to form a functionalized polymer in which the residue ofaddition group A links R⁴ to the polymer. Where R⁴ is a bond between Aand α, the residue of addition group A links α to the polymer. Thus, R⁴and the residue of A together comprise R¹ of Formula I above. In otherwords, R¹ includes the residue of an addition reaction between anaddition group and a living polymer.

Preferably, A is a moiety comprising a nitrile, such as a cyano group,an alkyl or alkenyl nitrile; a Schiff base, generally represented asRR′C═NR″; or a ketone group, an aldehyde group, or an ester group. Morepreferably, A comprises a nitrile moiety.

In the embodiment where the functionalizing agent is an additionfunctionalizing agent, α preferably comprises an aromatic or partiallyunsaturated sulfur-containing heterocycle. More preferably, α comprisesa benzothiazole, thiophene, or thiazoline moiety.

Specific examples of suitable addition functionalizing agents include2-benzothiazoleacetonitrile, 2-cyanothiophene, 3-cyanothiophene,2-acetothiophene, and 2-thienylcarboxaldehyde.

The method of this invention is useful for functionalizing ananionically polymerized living polymer. Anionically-polymerized livingpolymers are formed by reacting anionic initiators with certainunsaturated monomers to propagate a polymeric structure. Throughoutformation and propagation of the polymer, the polymeric structure isanionic and “living.” A new batch of monomer subsequently added to thereaction can add to the living ends of the existing chains and increasethe degree of polymerization. A living polymer, therefore, is apolymeric segment having a living or reactive end. Anionicpolymerization is further described in George Odian, Principles ofPolymerization, ch. 5 (3^(rd) Ed. 1991), or Panek, 94 J. Am. Chem. Soc.,8768 (1972), which are incorporated herein by reference.

Monomers that can be employed in preparing an anionically polymerizedliving polymer include any monomer capable of being polymerizedaccording to anionic polymerization techniques. These monomers includethose that lead to the formation of elastomeric homopolymers orcopolymers. Suitable monomers include, without limitation, conjugatedC₄-C₁₂ dienes, C₈-C₁₈ monovinyl aromatic monomers, and C₆-C₂₀ trienes.Examples of conjugated diene monomers include, without limitation,1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, and1,3-hexadiene. A non-limiting example of trienes includes myrcene.Aromatic vinyl monomers include, without limitation, styrene, α-methylstyrene, p-methylstyrene, and vinylnaphthalene. When preparingelastomeric copolymers, such as those containing conjugated dienemonomers and aromatic vinyl monomers, the conjugated diene monomers andaromatic vinyl monomers are normally used at a ratio of 95:5 to 50:50,and preferably 95:5 to 65:35.

Any anionic initiator can be employed to initiate the formation andpropagation of the living polymers. Exemplary anionic initiatorsinclude, but are not limited to, alkyl lithium initiators such asn-butyl lithium, arenyllithium initiators, arenylsodium initiators,N-lithium dihydro-carbon amides, aminoalkyllithiums, and alkyl tinlithiums. Other useful initiators include N-lithiohexamethyleneimide,N-lithiopyrrolidinide, and N-lithiododecamethyleneimide as well asorganolithium compounds such as the tri-alkyl lithium adducts ofsubstituted aldimines and substituted ketimines, and N-lithio salts ofsubstituted secondary amines. Exemplary initiators are also described inthe following U.S. Pat. Nos. 5,332,810, 5,329,005, 5,578,542, 5,393,721,5,698,646, 5,491,230, 5,521,309, 5,496,940, 5,574,109, and 5,786,441,which are incorporated herein by reference.

For purposes of this specification, the head of the polymer will referto that point of the polymer main chain where the initiator adds to thefirst monomer. The tail will therefore refer to that point of thepolymer substituent main chain where the last monomer is added to thechain, which is likewise the point where the polymer is attached to theR¹-α group of Formula I. With this understanding, the polymer (π) maylikewise include a functional group at the head of the polymer, whichresults from initiating polymerization with a functionalized initiator.These functional groups may include any of the various functional groupsthat react or interact with rubber or rubber fillers or otherwise have adesirable impact on filled rubber compositions or vulcanizates. Usefulfunctionalized initiators include trialkyltin lithium compounds andlithio-cyclic amine compounds. Exemplary tin lithio-containinginitiators are disclosed in U.S. Pat. No. 5,268,439, which isincorporated herein by reference. Exemplary lithio-cyclic aminoinitiators are disclosed in U.S. Pat. Nos. 6,080,835, 5,786,441,6,025,450, and 6,046,288, which are incorporated herein by reference.Other functional groups include those groups that interact with fillervia through-space interaction (e.g., H-bonding, van der Waalsinteraction, etc.) as well as those groups that interact with or attractto each other and thereby form a domain within the rubber matrix of thepolymer. Still others include selective functional groups whose affinitytoward filler particles or rubber can be activated after processing,e.g., during cure. Examples of selective functional groups include thosedescribed in U.S. Pat. No. 6,579,949.

The amount of initiator employed in conducting anionic polymerizationscan vary widely based upon the desired polymer characteristics. In oneembodiment, it is preferred to employ from about 0.1 to about 100, andmore preferably from about 0.33 to about 10 mmol of lithium per 100 g ofmonomer.

Anionic polymerizations are typically conducted in a polar solvent suchas tetrahydrofuran (THF) or a nonpolar hydrocarbon such as the variouscyclic and acyclic hexanes, heptanes, octanes, pentanes, their alkylatedderivatives, and mixtures thereof, as well as benzene.

In order to promote randomization in copolymerization and to controlvinyl content, a polar coordinator may be added to the polymerizationingredients. Amounts range between 0 and 90 or more equivalents perequivalent of lithium. The amount depends on the amount of vinyldesired, the level of styrene employed and the temperature of thepolymerization, as well as the nature of the specific polar coordinator(modifier) employed. Suitable polymerization modifiers include, forexample, ethers or amines to provide the desired microstructure andrandomization of the comonomer units.

Compounds useful as polar coordinators include those having an oxygen ornitrogen heteroatom and a non-bonded pair of electrons. Examples includedialkyl ethers of mono and oligo alkylene glycols; “crown” ethers;tertiary amines such as tetramethylethylene diamine (TMEDA); linear THFoligomers; and the like. Specific examples of compounds useful as polarcoordinators include tetrahydrofuran (THF), linear and cyclic oligomericoxolanyl alkanes such as 2,2-bis(2′-tetrahydrofuryl)propane,di-piperidyl ethane, dipiperidyl methane, hexamethylphosphoramide,N—N′-dimethylpiperazine, diazabicyclooctane, dimethyl ether, diethylether, tributylamine and the like. The linear and cyclic oligomericoxolanyl alkane modifiers are described in U.S. Pat. No. 4,429,091,incorporated herein by reference.

Anionically polymerized living polymers can be prepared by either batchor continuous methods. A batch polymerization is begun by charging ablend of monomer(s) and normal alkane solvent to a suitable reactionvessel, followed by the addition of the polar coordinator (if employed)and an initiator compound. The reactants are heated to a temperature offrom about 20 to about 130° C. and the polymerization is allowed toproceed for from about 0.1 to about 24 hours. This reaction produces areactive polymer having a reactive or living end. Preferably, at leastabout 30% of the polymer molecules contain a living end. Morepreferably, at least about 50% of the polymer molecules contain a livingend. Even more preferably, at least about 80% contain a living end.

A continuous polymerization is begun by charging monomer(s), initiatorand solvent at the same time to a suitable reaction vessel. Thereafter,a continuous procedure is followed that removes product after a suitableresidence time and replenishes the reactants.

The functionalizing agent is reacted with the living polymer end. Thisreaction can be achieved by simply mixing the functionalizing agent withthe living polymer. In a preferred embodiment, the functionalizing agentis added once a peak polymerization temperature, which is indicative ofnearly complete monomer conversion, is observed. Because live ends mayself-terminate, it is especially preferred to add the functionalizingagent within about 25 to 35 minutes of the peak polymerizationtemperature.

The amount of functionalizing agent employed to prepare thefunctionalized polymers is best described with respect to theequivalents of lithium or metal cation within the initiator.Accordingly, where a lithium initiator is employed, the ratio ofequivalents of functionalizing agent to equivalents of lithium ispreferably about 0.75:1, more preferably about 0.85:1, even morepreferably about 0.95:1, and most preferably at least about 1:1.

In certain embodiments of this invention, the functionalizing agent canbe employed in combination with other coupling or terminating agents.The combination of functionalizing agent with other terminating agent orcoupling agent can be in any molar ratio. The coupling agents that canbe employed in combination with the functionalizing agent include any ofthose coupling agents known in the art including, but not limited to,tin tetrachloride, tetraethyl ortho silicate, and tetraethoxy tin, andsilicon tetrachloride. Likewise, any terminating agent can be employedin combination with the functionalizing agent including, but not limitedto, tributyltin chloride.

After formation of the functional polymer, a processing aid and otheroptional additives such as oil can be added to the polymer cement. Thefunctional polymer and other optional ingredients are then isolated fromthe solvent and preferably dried. Conventional procedures fordesolventization and drying may be employed. In one embodiment, thefunctional polymer may be isolated from the solvent by steamdesolventization or hot water coagulation of the solvent followed byfiltration. Residual solvent may be removed by using conventional dryingtechniques such as oven drying or drum drying. Alternatively, the cementmay be directly drum dried.

The functionalized polymers of this invention are particularly useful inpreparing tire components. These tire components can be prepared byusing the functionalized polymers of this invention alone or togetherwith other rubbery polymers. Other rubbery elastomers that may be usedinclude natural and synthetic elastomers. The synthetic elastomerstypically derive from the polymerization of conjugated diene monomers.These conjugated diene monomers may be copolymerized with other monomerssuch as vinyl aromatic monomers. Other rubbery elastomers may derivefrom the polymerization of ethylene together with one or more α-olefinsand optionally one or more diene monomers.

Useful rubbery elastomers include natural rubber, syntheticpolyisoprene, polybutadiene, polyisobutylene-co-isoprene, neoprene,poly(ethylene-co-propylene), poly(styrene-co-butadiene),poly(styrene-co-isoprene), and poly(styrene-co-isoprene-co-butadiene),poly(isoprene-co-butadiene), poly(ethylene-co-propylene-co-diene),polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber,epichlorohydrin rubber, and mixtures thereof. These elastomers can havea myriad of macromolecular structures including linear, branched andstar shaped. Other ingredients that are typically employed in rubbercompounding may also be added.

The rubber compositions may include fillers such as inorganic andorganic fillers. The organic fillers include carbon black and starch.The inorganic fillers may include silica, aluminum hydroxide, magnesiumhydroxide, clays (hydrated aluminum silicates), and mixtures thereof.

A multitude of rubber curing agents may be employed, including sulfur orperoxide-based curing systems. Curing agents are described in 20Kirk-Othmer, Encyclopedia of Chemical Technology, 365-468, (3^(rd) Ed.1982), particularly Vulcanization Agents and Auxiliary Materials,390-402, and A. Y. Coran, Vulcanization in Encyclopedia of PolymerScience and Engineering, (2^(nd) Ed. 1989), which are incorporatedherein by reference. Vulcanizing agents may be used alone or incombination.

Other ingredients that may be employed include accelerators, oils,waxes, scorch inhibiting agents, processing aids, zinc oxide, tackifyingresins, reinforcing resins, fatty acids such as stearic acid, peptizers,and one or more additional rubbers.

These stocks are useful for forming tire components such as treads,subtreads, black sidewalls, body ply skins, bead filler, and the like.Preferably, the functional polymers are employed in tread formulations,and these tread formulations will include from about 10 to about 100% byweight of the functional polymer based on the total rubber within theformulation. More preferably, the tread formulation will include fromabout 35 to about 90% by weight, and more preferably from about 50 to80% by weight of the functional polymer based on the total weight of therubber within the formulation. The preparation of vulcanizablecompositions and the construction and curing of the tire is not affectedby the practice of this invention.

Preferably, the vulcanizable rubber composition is prepared by formingan initial masterbatch that includes the rubber component and filler.This initial masterbatch is mixed at a starting temperature of fromabout 25° C. to about 125° C. with a discharge temperature of about 135°C. to about 180° C. To prevent premature vulcanization (also known asscorch), this initial masterbatch generally excludes any vulcanizingagents. Once the initial masterbatch is processed, the vulcanizingagents are introduced and blended into the initial masterbatch at lowtemperatures in a final mix stage, which does not initiate thevulcanization process. Optionally, additional mixing stages, sometimescalled remills, can be employed between the masterbatch mix stage andthe final mix stage. Rubber compounding techniques and the additivesemployed therein are generally known as disclosed in Stephens, TheCompounding and Vulcanization of Rubber, in Rubber Technology (2^(nd)Ed. 1973). The mixing conditions and procedures applicable tosilica-filled tire formulations are also well known as described in U.S.Pat. Nos. 5,227,425, 5,719,207, 5,717,022, and European Patent No.890,606, all of which are incorporated herein by reference.

Where the vulcanizable rubber compositions are employed in themanufacture of tires, these compositions can be processed into tirecomponents according to ordinary tire manufacturing techniques includingstandard rubber shaping, molding and curing techniques. Typically,vulcanization is effected by heating the vulcanizable composition in amold; e.g., it is heated to about 140 to about 180° C. Cured orcrosslinked rubber compositions may be referred to as vulcanizates,which generally contain three-dimensional polymeric networks that arethermoset. The other ingredients, such as processing aides and fillers,are generally evenly dispersed throughout the vulcanized network.Pneumatic tires can be made as discussed in U.S. Pat. Nos. 5,866,171,5,876,527, 5,931,211, and 5,971,046, which are incorporated herein byreference.

In order to demonstrate the practice of the present invention, thefollowing examples have been prepared and tested. The examples shouldnot, however, be viewed as limiting the scope of the invention. Theclaims will serve to define the invention.

EXAMPLES Example 1 Control Polymer

To a 18.9 L reactor equipped with turbine agitator blades was added 4.91kg hexane, 1.25 kg (32.8 wt %) styrene in hexane, and 7.37 kg (22.2 wt%) butadiene in hexane. To the reactor was charged 11.60 mL of 1.6 Mbutyllithium in hexane and 3.83 mL of 1.6 M2,2′-di(tetrahydrofuryl)propane in hexane and the batch temperature wascontrolled at 49° C. After approximately 1 hour, the batch was cooled to32° C. and a measured amount of live poly(styrene-co-butadiene)cementwas then transferred to a sealed nitrogen purged 800 mL bottle. Thebottle contents were then terminated with isopropanol, coagulated anddrum dried.

Example 2 2-Methyl-2-thiazoline Functionalized Polymer

A second bottle of cement was transferred from the 18.9 L reactor usedin Example 1 and to this was added 1 equivalent of2-methylthio-2-thiazoline per butyllithium. The bottle contents werethen coagulated and drum dried. The polymers of Examples 1 and 2 werecharacterized as set forth in Table I.

TABLE I Example No. 1 2 M_(n) (kg/mol) 120 130 M_(w) (kg/mol) 127 154T_(g) (° C.) −31.6 −31.6 Styrene (%) 21.0 21.0 Block Styrene (%) 1.9 1.91,2-butadiene (% of butadiene) 56.8 56.8

Examples 3 and 4 Carbon Black Rubber Formulations

The rubber of Examples 1 and 2 were employed in tire formulations. Theformulations are presented in Table II. More specifically, the rubber ofExample 1 was incorporated in the formulation of Example 3. The rubberof Example 2 was incorporated in the formulation of Example 4.

TABLE II Example No. 3 4 Initial Formulation Example 1 (weight parts)100 0 Example 2 (weights parts) 0 100 Carbon Black 55 55 Wax 1 1Antioxidant 0.95 0.95 Zinc Oxide 2.5 2.5 Stearic Acid 2 2 Aromatic Oil10 10 Total 171.45 171.45 Final Formulation Initial 171.45 171.45 Sulfur1.3 1.3 Accelerators 1.9 1.9 Total 174.65 174.65

Each rubber compound was prepared in two portions named Initial andFinal. In the initial part, the polymer from Example 1 or 2 was mixedwith carbon black, an antioxidant, stearic acid, wax, aromatic oil, andzinc oxide, in a 65 g Banbury mixer operating at 60 rpm and 133° C.Specifically, the polymer was first placed in the mixer, and after 0.5minutes, the remaining ingredients except the stearic acid were added.The stearic acid was then added after 3 minutes. The initials were mixedfor 5-6 minutes. At the end of the mixing the temperature wasapproximately 165° C. The sample was transferred to a mill operating ata temperature of 60° C., where it was sheeted and subsequently cooled toroom temperature.

The finals were mixed by adding the initials and the curative materialsto the mixer simultaneously. The initial mixer temperature was 65° C.and it was operating at 60 rpm. The final material was removed from themixer after 2.25 minutes when the material temperature was between 100and 105° C.

TABLE III Example No. 3 4 ML₁₊₄ @ 130° C. 29.1 44.4 t₅ (min) 22.1 18.3200% Modulus @ 23° C. (MPa) 7.28 8.18 Tensile @ Break @ 23° C. (MPa)15.81 16.09 Elongation @ Break @ 23° C. (%) 380 327 tan δ @ 5% E (50°C., 1 Hz) 0.258 0.135 ΔG′ (50° C.) (MPa)* 4.06 0.97 tan δ @ 0.5% E (0°C., 5 Hz) 0.242 0.392 Shore A Peak (23° C.) 72.2 68.7 *ΔG′ = G′ (@0.25%E) − G′ (@14.5% E)

Test specimens of each rubber formulation were prepared by cutting outthe required mass from an uncured sheet (about 2.5 mm to 3.81 mm thick),and cured within closed cavity molds under pressure for 15 minutes at171° C. The test specimens were then subjected to various physicaltests, and the results of these tests are reported in Table III. Modulusat 200%, elongation at break, and tensile strength were measuredaccording to ASTM D 412 (1998) Method B, where samples were died from acured sheet about 1.8 mm thick. Dynamic properties of rubber cylindersmeasuring about 9.5 mm in diameter and 16 mm high were analyzed by usinga RDA (Rheometrics Dynamic Analyzer). Mooney viscosity measurements wereconducted according to ASTM-D 1649-89.

Example 5 Synthesis of 2-Benzylthio-2-thiazoline

To a dry, nitrogen (N₂)-purged 500 milliliter (mL) round bottom flaskwas added 1.15 grams (g) (4.8 mmol) sodium hydride. To this was added150 mL dry tetrahydrofuran and 5.70 g (4.8 mmol) 2-mercaptothiazoline in24 mL tetrahydrofuran. After approximately 15 minutes of stirring atroom temperature, 5.5 mL (4.8 mmol) benzyl chloride was added andstirred for an additional 5 minutes. Tetrahydrofuran was removed byrotary evaporation and product was dissolved in hexane. Afterfiltration, the product was recrystallized from hexane to yield 2.6 g ofwhite crystals (26% yield). ¹H NMR (CDCl₃): 3.434 ppm, t, 2H; 4.259 ppm,t, 2H; 4.413 ppm, s, 2H; 7.317 ppm, m, 5H.

Example 6 Synthesis of 2-Dodecylthio-2-thiazoline

To a dry, N₂-purged 500 mL three-necked round bottom flask was added1.30 g (4.7 mmol) of sodium hydride. To this was added 150 mL driedtetrahydrofuran and 5.70 g (4.8 mmol) of 2-mercaptothiazoline. Afterapproximately 15 minutes of stirring at room temperature, 11.48 mL (4.8mmol) of 1-bromododecane was added and stirred for 1 hour. The solutionwas rotary evaporated and the product dissolved in diethylether. Thesolution was extracted with three 50 mL aliquots of H₂O and dried overanhydrous MgSO₄. Product (3.16 g, 23% yield) was eluted from a neutralalumina column using pentane. ¹H NMR (CDCl₃): 0.88 ppm, t, 3H; 1.28 ppm,m, 16H; 1.38 ppm, p, 2H; 1.67 ppm, p, 2H; 3.09 ppm, t, 2H; 3.38 ppm, t,2H; 4.21 ppm, t, 2H.

Example 7 Synthesis of 2-Dimethylamino-2-thiazoline

To a dry, N₂-purged 500 mL three-necked flask equipped with refluxcondenser and magnetic stirrer was added 100 mL dry THF under N₂. Tothis was added 41.1 mL of 2M (8.2 mmol) dimethylamine in THF. Then, 10 g(8.2 mmol) of 2-chloroethylisothiocyanate was added and a precipitateformed. To this was added 6.06 g (0.082 mmol) lithium carbonate andsolution was refluxed for approximately 4 hours. After 48 hours, anadditional 25 mL of 2.0 M (5.0 mmol) dimethylamine in THF was added andrefluxed for 4 hours. Solvent was removed and product dissolved in 150mL diethylether. This was extracted with three 50 mL aliquots of H₂O,dried with anhydrous MgSO₄, and rotary evaporated to yield 2.34 g (22%yield) of 2-dimethylamino-2-thiazoline. ¹H NMR (CDCl₃): 2.98 ppm, s, 6H;3.32 ppm, t, 2H; 4.01 ppm, t, 2H.

Example 8 Control Polymer

Example 8 was prepared as in Example 1.

Example 9 2-Benzylthio-2-thiazoline Functionalized Polymer

Example 9 was prepared as in Example 2, except that 1 equivalent of2-benzylthio-2-thiazoline was added to the polymer cement instead of2-methylthio-2-thiazoline.

Example 10 Control Polymer

Example 10 was prepared as in Example 1.

Example 11 2-Dodecylthio-2-thiazoline Functionalized Polymer

Example 11 was prepared as in Example 2, except that 1 equivalent of2-dodecylthio-2-thiazoline was added to the polymer cement instead of2-methylthio-2-thiazoline.

Example 12 Control Polymer

Example 12 was prepared as in Example 1.

Example 13 2-Dimethylamino-2-thiazoline Functionalized Polymer

Example 13 was prepared as in Example 2, except that 1 equivalent of2-dimethylamino-2-thiazoline was added to the polymer cement instead of2-methylthio-2-thiazoline.

The polymers of Examples 8-13 were characterized as set forth in TableIV.

TABLE IV Example No. 8 9 10 11 12 13 Mn (kg/mol) 115 121 93 126 141 151Mw (kg/mol) 123 155 100 163 151 180 Tg (° C.) −30 −31.2 −35.4 −35.2−31.7 −31.6 Styrene (%) 21.2 21.3 21.4 21.1 20.4 20.4 Block Styrene (%)2.4 2.5 2.4 2.3 2.5 2.5 1,2-butadiene 57.6 58.1 54.0 52.4 58.1 58.1 (%of butadiene)

Examples 14-19 Carbon Black Rubber Formulations

The rubber of Examples 8-13 was employed in tire formulations. Theformulations, denoted Examples 14-19, are presented in Table V.

TABLE V Example No. 14 15 16 17 18 19 Initial Formulation Rubber 8 9 1011 12 13 Example No. Rubber (weight 100 100 100 100 100 100 parts)Carbon Black 55 55 55 55 55 55 Wax 1 1 1 1 1 1 Antioxidant 0.95 0.950.95 0.95 0.95 0.95 Zinc Oxide 2.5 2.5 2.5 2.5 2.5 2.5 Stearic Acid 2 22 2 2 2 Aromatic Oil 10 10 10 10 10 10 Total 171.45 171.45 171.45 171.45171.45 171.45 Final Formulation Initial 171.45 171.45 171.45 171.45171.45 171.45 Sulfur 1.3 1.3 1.3 1.3 1.3 1.3 Accelerators 1.9 1.9 1.91.9 1.9 1.9 Total 174.65 174.65 174.65 174.65 174.65 174.65

Each carbon black rubber compound was prepared in two stages, asdescribed above for Examples 3 and 4. Test specimens were prepared andsubjected to various physical tests as for Examples 3 and 4. The resultsof these tests are reported in Table VI. Modulus at 300%, elongation atbreak, and tensile strength were measured according to ASTM D 412 (1998)Method B, where samples were died from a cured sheet about 1.8 mm thick.MH-ML and MDA t₅₀ were measured according to ASTM-D 2084 on a Moving DieRheometer (MDR).

Bound rubber, a measure of the percentage of rubber bound, through someinteraction, to the filler, was determined by solvent extraction withtoluene at room temperature. More specifically, a test specimen of eachuncured rubber formulation was placed in toluene for three days. Thesolvent was removed and the residue was dried and weighed. Thepercentage of bound rubber was then determined according to the formula% bound rubber=(100(W _(d) −F))/Rwhere W_(d) is the weight of the dried residue, F is the weight of thefiller and any other solvent insoluble matter in the original sample,and R is the weight of the rubber in the original sample.

TABLE VI Example No. 14 15 16 17 18 19 ML1 + 4@130° C. 27.4 42 26.6 41.136.2 46.4 MH-ML @ 171° C. 18.82 18.04 18.83 17.18 19.72 18.48 (Kg/cm)MDR t₅₀ @ 171° C. (min) 3.1 2.8 2.9 3.0 3.1 2.9 300% Modulus @ 11.2114.39 11.07 12.73 12.2 13.15 23° C. (MPa) Tensile @ Break @ 17.77 16.8816.84 19.59 16.02 15.5 23° C. (MPa) tan δ @ 2% E 0.219 .0277 .0199 .0253.0254 .0271 (0° C., 5 Hz) tan δ @ 2% E 0.243 0.178 0.242 0.214 0.2530.232 (50° C., 5 Hz) tan δ @ 5% E 0.245 0.144 0.249 0.147 0.225 0.163(50° C., 1 Hz) ΔG′ (50° C.) (MPa)* 4.571 1.17 5.156 1.212 4.196 1.798Bound Rubber (%) 14.5 35.6 13.4 34.1 16.1 29.2 *ΔG′ = G′ (@0.25% E) − G′(@14.5% E)

Example 20 Control Polymer

To a 18.9 L reactor equipped with turbine agitator blades was added 4.93kg hexane, 1.20 kg (34 wt %) styrene in hexane, and 7.40 kg (22.1 wt %)butadiene in hexane. To the reactor was charged 11.25 mL of 1.6 Mbutyllithium in hexane and 3.83 mL of 1.6 M2,2′-di(tetrahydrofuryl)propane in hexane and the batch temperature wascontrolled at 49° C. After approximately 1 hour, the batch was cooled to32° C. and a measured amount of live poly(styrene-co-butadiene) cementwas then transferred to a sealed nitrogen purged 800 mL bottle. Thebottle contents were then terminated with isopropanol, coagulated anddrum dried.

Example 21 2-Benzothiazoleacetonitrile Functionalized Polymer

A second bottle of cement was transferred from the 18.9 L reactor usedin Example 20 and to this was added 1 equivalent of2-benzothiazoleacetonitrile per butyllithium. The bottle contents werethen coagulated and drum dried. The polymers of Examples 20 and 21 werecharacterized as set forth in Table VII.

TABLE VII Example No. 20 21 M_(n) (kg/mol) 119 117 M_(w) (kg/mol) 127123 T_(g) (° C.) −33.1 −33.1 Styrene (%) 20.5 20.5 Block Styrene (%) 2.02.0 1,2-butadiene (% of butadiene) 56.1 56.1

The rubber of Examples 20 and 21 were employed in carbon black andcarbon black/silica tire formulations. The formulations are presented inTable VIII. More specifically, the rubber of Example 20 was incorporatedin the formulations of Examples 22 and 24. The rubber of Example 6 wasincorporated in the formulations of Examples 23 and 25.

TABLE VIII Example No. 22 23 24 25 Example 20 (weight parts) 100 0 100 0Example 21 (weight parts) 0 100 0 100 Carbon Black 55 55 35 35 Silica 00 30 30 Wax 1 1 0 0 Antiozonant 0.95 0.95 0.95 0.95 Zinc Oxide 2.5 2.5 00 Stearic Acid 2 2 1.5 1.5 Aromatic Oil 10 10 10 10 Total 171.45 171.45177.45 177.45 Remill Initial N/A N/A 177.45 177.45 Silane ShieldingAgent N/A N/A 4.57 4.57 Total 171.45 171.45 182.02 182.02 FinalFormulation Initial 171.45 171.45 182.02 182.02 Sulfur 1.3 1.3 1.7 1.7Zinc Oxide 0 0 2.5 2.5 Accelerators 1.9 1.9 2.25 2.25 Total 174.65174.65 188.47 188.47

Examples 22 and 23 Carbon Black Rubber Formulations

Each carbon black rubber compound was prepared in two stages, as forExamples 3 and 4 above. Test specimens of each rubber formulation wereprepared and subjected to various physical tests, as for Examples 3 and4 above. The results of these tests are reported in Table IX. Modulus at300% and tensile strength were measured according to ASTM D 412 (1998)Method B. Dynamic properties were determined by using a RheometricsDynamic Analyzer (RDA).

Examples 24 and 25 Carbon Black/Silica Rubber Formulations

Each carbon black/silica rubber compound was prepared in three stagesnamed Initial, Remill and Final. In the initial part, the polymer fromExamples 20 or 21 was mixed with carbon black, silica, an antioxidant,stearic acid, and aromatic oil in a 65 g Banbury mixer operating at 60RPM and 133° C. Specifically, the polymer was first placed in the mixer,and after 0.5 minutes, the remaining ingredients except the stearic acidwere added. The stearic acid was then added after 3 minutes. Theinitials were mixed for 5-6 minutes. At the end of the mixing thetemperature was approximately 165° C. The sample was cooled to less thatabout 95° C. and transferred to a remill mixer.

In the remill stage, the initial formulation and a silane shieldingagent were simultaneously added to a mixer operating at about 60 RPM.The shielding agent employed in these examples was EF(DiSS)-60,available from Rhein Chemie Corp. The starting temperature of the mixerwas about 94° C. The remill material was removed from the mixer afterabout 3 minutes, when the material temperature was between 135 and 150°C.

The finals were mixed by adding the remills, zinc oxide and the curativematerials to the mixer simultaneously. The initial mixer temperature was65° C. and it was operating at 60 RPM. The final material was removedfrom the mixer after 2.25 minutes when the material temperature wasbetween 100 and 105° C. The test specimens were prepared and subjectedto various physical tests as for Examples 3-4 above. The results ofthese tests are reported in Table IX.

TABLE IX Example No. 22 23 24 25 ML₁₊₄ @ 130° C. 24.0 32.9 57.4 72.8 t₅(min) 22.9 21.8 38.1 30.3 200% Modulus @ 23° C. (MPa) 6.56 6.66 6.456.88 Tensile @ Break @ 23° C. (MPa) 16.76 16.67 13.24 14.77 ElongationBreak 23° C. (%) 419 393 417 396 tan δ @ 0.5% E (0° C., 5 Hz) 0.2330.255 0.235 0.235 ΔG′ (50° C.) (MPa)** 4.803 1.202 7.226 2.755 tan δ @5% E (50° C., 1 Hz) 0.260 0.155 0.242 0.180 Shore A Peak (23° C.) 73.169.4 78.3 75.9 **ΔG′ = G′ (@0.25% E) − G′ (@14.5% E)

Example 26 Control Polymer

To a 18.9 L reactor equipped with turbine agitator blades was added 4.83kg hexane, 1.20 kg (34 wt %) styrene in hexane, and 7.50 kg (22.1 wt %)butadiene in hexane. To the reactor was charged 11.25 mL of 1.6 Mbutyllithium in hexane and 3.83 mL of 1.6 M2,2′-di(tetrahydrofuryl)propane in hexane and the batch temperature wascontrolled at 49° C. After approximately 1 hour, the batch was cooled to32° C. and a measured amount of live poly(styrene-co-butadiene)cementwas then transferred to a sealed nitrogen purged 800 mL bottle. Thebottle contents were then terminated with isopropanol, coagulated anddrum dried.

Example 27 2-Thiophenecarbonitrile Functionalized Polymer

A second bottle of cement was transferred from the 18.9 L reactor usedin Example 26 and to this was added 1 equivalent of2-thiophenecarbonitrile per butyllithium. The bottle contents were thencoagulated and drum dried. The polymers of Examples 26 and 27 werecharacterized as set forth in Table X.

TABLE X Example No. 26 27 M_(n) (kg/mol) 124 124 M_(w) (kg/mol) 134 135T_(g) (° C.) −34.6 −34.6 Styrene (%) 19.9 19.9 Block Styrene (%) 1.8 1.81,2-butadiene (% of butadiene) 56.2 56.2

The rubber of Examples 26 and 27 were employed in carbon black andcarbon black/silica tire formulations. The formulations are presented inTable XI. More specifically, the rubber of Example 26 was incorporatedin the formulations of Examples 28 and 30. The rubber of Example 27 wasincorporated in the formulations of Examples 29 and 31.

TABLE XI Example No. 28 29 30 31 Example 26 (weight parts) 100 0 100 0Example 27 (weight parts) 0 100 0 100 Carbon Black 55 55 35 35 Silica 00 30 30 Wax 1 1 0 0 Antiozonant 0.95 0.95 0.95 0.95 Zinc Oxide 2.5 2.5 00 Stearic Acid 2 2 1.5 1.5 Aromatic Oil 10 10 10 10 Total 171.45 171.45177.45 177.45 Remill Initial N/A N/A 177.45 177.45 Silane ShieldingAgent N/A N/A 4.57 4.57 Total 171.45 171.45 182.02 182.02 FinalFormulation Initial 171.45 171.45 182.02 182.02 Sulfur 1.3 1.3 1.7 1.7Zinc Oxide 0 0 2.5 2.5 Accelerators 1.9 1.9 2.25 2.25 Total 174.65174.65 188.47 188.47

Examples 28 and 29 Carbon Black Rubber Formulations

Each carbon black rubber compound was prepared in two stages, as forExamples 3 and 4 above. Test specimens of each rubber formulation wereprepared and subjected to various physical tests, as for Examples 3 and4 above. The results of these tests are reported in Table XII. Modulusat 300% and tensile strength were measured according to ASTM D 412(1998) Method B. Dynamic properties were determined by using aRheometrics Dynamic Analyzer (RDA).

Examples 30 and 31 Carbon Black/Silica Rubber Formulations

Each carbon black/silica rubber compound was prepared in three stages,as in Examples 24 and 25 above. The test specimens were prepared andsubjected to various physical tests as for Examples 3-4 above. Theresults of these tests are reported in Table XII.

TABLE XII Example No. 28 29 30 31 ML₁₊₄ @ 130° C. 28.0 35.5 62.6 69.5 t₅(min) 20.63 20.72 36.3 37.4 300% Modulus @ 23° C. (MPa) 12.08 13.69 8.99.9 Tensile @ Break @ 23° C. (MPa) 17.88 18.27 13.4 14.5 ElongationBreak 23° C. (%) 416 374 448 429 tan δ @ 0.5% E (0° C., 5 Hz) 0.2320.266 0.211 0.214 ΔG′ (50° C.) (MPa)** 4.200 1.169 7.43 4.70 tan δ @ 5%E (50° C., 1 Hz) 0.242 0.143 0.230 0.203 Shore A Peak (23° C.) 73.4 69.678.3 78.2 **ΔG′ = G′ (@0.25% E) − G′ (@14.5% E)

Example 32 Synthesis of2-(N-methyl-N-3-trimethoxysilylpropyl)-thiazoline

To a 500 mL round bottom flask was added 200 mL dry diethylether and15.4 g (126 mmol) chloroethylisothiocyanate. To this was added 25 mL(126 mmol) of N-methylaminopropyltrimethoxysilane. Once bubbling hadsubsided 13.4 g of sodium carbonate was added and solution was refluxedovernight. Product was filtered and solvent was removed by rotaryevaporation. 1H-NMR(CDCl₃): 3.95 ppm, t, 2H; 3.51 ppm, s, 9H; 3.20 ppm,t, 2H; 2.93 ppm, s, 3H; 1.62 ppm, m, 2H; 0.55 ppm, t, 2H. GC/MS showed94.2% pure product.

Example 33 Control Polymer

Example 33 was prepared as in Example 20.

Example 34 2-(N-methyl-N-3-trimethoxysilylpropyl)thiazolineFunctionalized Polymer

A second bottle of cement was transferred from the 18.9 L reactor usedin Example 33 and to this was added 1 equivalent of2-(N-methyl-N-3-trimethoxysilylpropyl)thiazoline per butyllithium. Thebottle contents were then coagulated and drum dried. The polymers ofExamples 33 and 34 were characterized as set forth in Table XIII.

TABLE XIII Example No. 33 34 M_(n) (kg/mol) 114 172 M_(w) (kg/mol) 119205 T_(g) (° C.) −35.0 −35.0 Styrene (%) 20.2 20.2 Block Styrene (%) 2.02.0 1,2-butadiene (% of butadiene) 54.4 54.4

Examples 35-38 Rubber Formulations

The rubber of Examples 33 and 34 were employed in carbon black andcarbon black/silica tire formulations. The formulations are presented inTable XIV. More specifically, the rubber of Example 33 was incorporatedin the formulations of Examples 35 and 37. The rubber of Example 34 wasincorporated in the formulations of Examples 36 and 38.

TABLE XIV Example No. 35 36 37 38 Example 33 (weight parts) 100 0 100 0Example 34 (weight parts) 0 100 0 100 Carbon Black 55 55 35 35 Silica 00 30 30 Wax 1 1 0 0 Antiozonant 0.95 0.95 0.95 0.95 Zinc Oxide 2.5 2.5 00 Stearic Acid 2 2 1.5 1.5 Aromatic Oil 10 10 10 10 Total 171.45 171.45177.45 177.45 Remill Initial N/A N/A 177.45 177.45 Silane ShieldingAgent N/A N/A 4.57 4.57 Total 171.45 171.45 182.02 182.02 FinalFormulation Initial 171.45 171.45 182.02 182.02 Sulfur 1.3 1.3 1.7 1.7Zinc Oxide 0 0 2.5 2.5 Accelerators 1.9 1.9 2.25 2.25 Total 174.65174.65 188.47 188.47

Each carbon black rubber compound was prepared in two stages, as forExamples 3 and 4 above. Test specimens of each rubber formulation wereprepared and subjected to various physical tests, as for Examples 3 and4 above. The results of these tests are reported in Table IX. Modulus at300% and tensile strength were measured according to ASTM D 412 (1998)Method B. Dynamic properties were determined by using a RheometricsDynamic Analyzer (RDA).

Each carbon black/silica rubber compound was prepared in three stages,as for Examples 24 and 25 above. The test specimens were prepared andsubjected to various physical tests as for Examples 3-4 above. Theresults of these tests are reported in Table XV.

TABLE XV Example No. 35 36 37 38 ML₁₊₄@130° C. 27.9 37.8 55.2 106.1 t₅(min) 21.5 21.6 41.1 19.7 200% Modulus @ 23° C. 6.08 7.22 6.33 7.87(MPa) Tensile @ Break @23° C. 16.23 17.78 11.67 13.33 (MPa) ElongationBreak 23° C. (%) 442.9 390.7 379 301 tan δ @ 0.5% E (0° C., 5 Hz) 0.2280.278 0.2069 0.2755 ΔG′ (50° C.) (MPa)** 4.674 1.367 6.584 1.732 tan δ @5% E (50° C., 1 Hz) 0.268 0.169 0.2525 0.1623 Shore A Peak (23° C.) 69.371.3 80.5 73.3 **ΔG′ = G′ (@0.25% E) − G′ (@14.5% E)

Various modifications and alterations that do not depart from the scopeand spirit of this invention will become apparent to those skilled inthe art. This invention is not to be duly limited to the illustrativeembodiments set forth herein.

1. A method for preparing a functional polymer, the method comprising:terminating a living polymer chain with a functionalizing agent wherethe functionalizing agent is defined by the formulaZ—R⁴-α where Z is a leaving group or an addition group, R⁴ is a bond ora divalent organic group, and α is a sulfur-containing heterocycleselected from the group consisting of thiirane, thietane, thiolane,thiazoline, dihydrothiophene, thiadiazine, thioxanthene, thianthrene,phenoxathiin, dihydroisothiazole, and thienofuran group or substitutedform thereof.
 2. The method of claim 1, where Z comprises a halide, athio alkoxide group, an alkoxide group, a dialkyl amine group, a nitrilegroup, a Schiff base, a ketone group, an aldehyde group, or an estergroup.
 3. The method of claim 1, where the polymer chain is a rubberypolymer having a Tg that is less than 0° C.
 4. The method of claim 1,where the polymer chain is polybutadiene, polyisoprene,poly(styrene-co-butadiene), poly(styrene-co-butadiene-co-isoprene),poly(isoprene-co-styrene), or poly(butadiene-co-isoprene).
 5. The methodof claim 1, where the functionalizing agent is defined by the formula

where L is a leaving group, R⁴ is a bond or a divalent organic group,each R² is independently hydrogen or a monovalent organic group, andeach R³ is independently hydrogen or a monovalent organic group or whereeach R³ combine with each other to form a divalent organic group.
 6. Themethod of claim 5, where the functionalizing agent is selected from thegroup consisting of 2-methylthio-2-thiazoline, 2-ethylthio-2-thiazoline,2-propylthio-2-thiazoline, 2-butylthio-2-thiazoline,2-pentylthio-2-thiazoline, 2-hexylthio-2-thiazoline,2-heptylthio-2-thiazoline, 2-dodecylthio-2-thiazoline,2-phenylthio-2-thiazoline, 2-benzylthio-2-thiazoline,2-chloro-2-thiazoline, 2-bromo-2-thiazoline, 2-iodo-2-thiazoline,2-dimethylamino-2-thiazoline, 2-diethylamino-2-thiazoline,2-methoxy-2-thiazoline, 2-ethoxy-2-thiazoline,2-(N-methyl-N-3-trimethoxysilylpropyl)-thiazoline, and2-methylthio-1-aza-3-thia-bicyclo[3-4-0]-nonene.
 7. The method of claim1, where the functionalizing agent is defined by the formula

where α is a sulfur-containing heterocycle selected from the groupconsisting of thiirane, thietane, thiolane, thiazoline,dihydrothiophene, thiadiazine, thioxanthene, thianthrene, phenoxathiin,dihydroisothiazole, and thienofuran group or substituted form thereofeach R⁵ is independently a monovalent organic group, and R⁶ is a bond ora divalent organic group.
 8. The method of claim 1, where thefunctionalizing agent is defined by the formula

where each R² is independently hydrogen or a monovalent organic group,each R³ is independently hydrogen or a monovalent organic group or whereeach R³ combine with each other to form a divalent organic group, eachR⁵ is independently a monovalent organic group, and R⁶ is a bond or adivalent organic group.
 9. The method of claim 1, where thefunctionalizing agent is2-(N-methyl-N-3-trimethoxysilylpropyl)thiazoline.